It sounds like you're experiencing a delay in the fee payment section for your DU SOL application. Here’s a step-by-step approach to address the issue:

1. **Follow Up with DU SOL**: Since you’ve already emailed them once, it’s worth following up if you don’t receive a response within a reasonable time. Ensure you include your application number and details to help them locate your application quickly.

2. **Check Application Portal Regularly**: Sometimes, system updates might take a bit longer. Make sure to check the application portal frequently for any updates or changes.

3. **Contact Technical Support**: Reach out to DU SOL’s technical support or helpline. They might offer more immediate assistance and can confirm if there are any issues with your application or payment system.

4. **Visit the DU SOL Office**: If possible, visit the DU SOL office in person. This can sometimes expedite the resolution of technical issues.

5. **Keep Records**: Maintain all records of correspondence and screenshots of your application status. This will be helpful if you need to escalate the issue.

Be patient, but persistent, as these issues are often resolved with a bit of follow-up.